The present invention relates to an enclosure connecting structure. More particularly, the invention relates to an electronic equipment enclosure connecting structure.
The enclosure connecting structure of the invention is used in a system consisting of a plurality of enclosures accommodating electronic equipment, similar to a large scale electronic computer system enclosure connecting structure which is excellent in maintainability of internal electronic equipment and requires short inter-equipment connecting cable length.
In a simple enclosure connecting structure of the prior art, a plurality of enclosures are closely arranged linearly. The enclosures accommodate electronic equipment and each enclosure is structured, for example, in the form of a locker. The electronic equipment accommodated in each enclosure is generally a multisurface rack structure including a single or plural and fixed or movable rack structure accommodating many printed circuit board units, power supply and cooling parts, etc. The equipment of the different enclosures is mutually connected via cable for sending and receiving signals. In the simple structure, however, the signal transmission time is a little delayed in accordance with the length of the connecting cable. Thus, in order to improve the operating speed of a computer system, the length of the connecting cable must be reduced. Therefore, enclosures used for a high speed operation are often arranged with their sides located in close proximity. On the other hand, in order to provide maintenance after delivery and installation on the user's premises, it is desirable that all surfaces of internal equipment, front and back, right and left, be exposed when the enclosure door is opened. This permits checking and maintenance from four sides, front and back, right and left. The enclosures are closely arranged, however, because of the cable length problem hereinbefore mentioned, since this is currently considered as the most important problem. For this reason, access or maintenance from the right side is lost for the left-most enclosure, while access or maintenance from both sides, right and left, are lost for the center enclosure.
As hereinbefore explained, the connecting structure makes maintenance from the side impossible, where the enclosures are closely arranged. These sides should thus have a structure which does not require any maintenance, thereby imposing a considerable restriction on the system design. Otherwise, it is necessary to stop the operation of the system, disconnect the cables, and separate the enclosures, in order to provide maintenance for the equipment.
Furthermore, advancement in high integration density of semiconductor parts provides an increase of input-output signal terminals of the printed circuit board unit mounting the equipment. This places a shelf and rack accommodating the equipment in a position which requires connecting terminals in multiple faces; that is, it increases the sides which require checking and maintenance. This tendency becomes distinctive as a system becomes large in scale, having more circuits in the higher integration density.
In another enclosure connecting structure of the prior art, an empty enclosure, which does not accommodate any electronic equipment for the purpose of connection, is provided. Each side of the empty enclosure is closely placed face to face with other enclosures through the inter-enclosure connection. Cables extending through the empty enclosure interconnect the equipment. The enclosures may thus be maintained, even at the connecting side, from the direction of the empty enclosure. Two of the enclosures may be maintained from all sides. A close layout is provided for the side which does not always require maintenance. In such a structure, the maintenance surface may be assured by providing the empty enclosure at the side where accessibility of maintainability is lost due to the close arrangement. However, the length of the cable becomes long and, simultaneously, a particular connecting enclosure must be provided, resulting in an increase of cost and an increase of useless installation space which cannot be used freely.
In still another connecting structure of the prior art, a longer connecting bus enclosure is used and the enclosures are arranged in zig-zag fashion on both sides of the bus enclosure through an inter-enclosure connection, with cables extending in said bus enclosure. In this case, the enclosures may be connected by the bus connection method, and the embodiment is particularly suitable for a large scale system. However, the lengths of the connecting cables become long, as in the foregoing embodiment, and maintenance of the enclosure at the side of the connecting or bus enclosure must be accomplished from the rear through said connecting enclosure, requiring extra installation space of said enclosure and thus increasing the cost.
The principal object of the invention is to provide an electronic equipment enclosure connecting structure which eliminates all the problems of known enclosure connecting structures.
An object of the invention is to provide an electronic equipment enclosure connecting structure which permits maintenance of, and access to, the equipment of a desired enclosure from several surfaces without use of a particular enclosure for connection.
Another object of the invention is to provide an electronic equipment enclosure connecting structure which shortens the length of the inter-enclosure connecting cables.